1. Field of the Invention
The present invention relates to a liquid crystal display (“LCD”) apparatus. More particularly, the present invention relates to a method for manufacturing a lens forming master used in manufacturing a transflective LCD apparatus and a method for manufacturing a thin-film transistor (“TFT”) substrate using a lens forming master.
2. Discussion of the Background
In general, a liquid crystal cell in an LCD panel adjusts a light transmission ratio according to a data signal, thereby displaying an image.
The LCD apparatus includes a transmissive type and a reflective type. The transmissive LCD displays an image using light that is irradiated from a backlight unit, and the reflective LCD displays an image by reflecting peripheral light, such as natural light. The transmissive LCD uses an additional rear-surface light source, so that a bright screen can be implemented even in a dark external environment, but power consumption is greater than with the reflective LCD. The reflective LCD consumes less power than the transmissive LCD because it uses peripheral light, but the reflective LCD apparatus can not be used in the dark.
Thus, a transflective LCD apparatus that can properly switch between two modes according to required conditions has been developed. The transflective LCD apparatus operates in a reflective mode when peripheral light is sufficient and operates in a transmissive mode using a backlight as a rear-surface light source when the peripheral light is not sufficient.
The transflective LCD apparatus includes a reflective area and a transmissive area. Peripheral light irradiated at various angles is condensed into a view angle in the reflective area, and rear-surface light provided from the backlight unit exits through a liquid crystal layer in the transmissive area.
The reflective area of the transflective LCD apparatus includes a protective surface. A lens for condensing the incident peripheral light into a user viewing angle is formed on the protective surface. The lens, which may have a complex shape, such as a fine shape or an asymmetric shape, improves the reflective ratio in the reflective area. However, a photolithography method for forming the lens in the protective layer of the transflective type LCD apparatus is limited with regard to lens shape, uniformity of processes, and reproducibility.
When a shape of a complex lens is formed by a conventional photolithography method, exposure processes may be increased and an expensive half-tone mask may be needed. Moreover, when the shape of the complex lens is formed by the conventional photolithography method, process parameters, such as the thickness of the protective layer and the amount of exposure, may be difficult to control, but should be controlled to assure process uniformity and reproducibility.